Flora of the Canadian Arctic Archipelago
Brassicaceae (Cruciferae), Draba family.
Published in Mem. Soc. Imp. Naturalistes Moscou 5: 103. 1817.
Type: Described from northern Siberia: "Habitat in Sibiria septentrionali ad ostium fluvii Dschulamda in Lenam, prope urbem Schigansk", leg. Adams. Syntypes: MW, G-DC (two specimens), and perhaps in LE.
Vegetative morphology. Plants 1.5–15(–25) cm high; perennial herbs; caespitose. Taproot present. Ground level or underground stems absent. Horizontal stems at ground level, branching extensively to shape plant habit as cushions. Caudex present (branched or unbranched near ground level). Aerial stems erect. Aerial stem trichomes spreading. Leaves mainly basal, or basal in a rosette (few cauline leaves); alternate; marcescent (with limited build-up at the base of the plant). Petioles absent (leaf bases not long attenuate, or sometimes petiole-like). Leaf blades simple. Leaf blade bases truncate, or attenuate. Leaves not grass-like. Blades (2–)5–15(–20) mm long, 1.5–2.5(–3) mm wide, spreading, obovate or oblanceolate, appearing single-veined or with inconspicuous veins. Blade adaxial surface hairy, hairs simple or branched (irregularly) or stellate, hairs moderately dense, hairs white, or translucent. Blade abaxial surface hairy, hairs very dense, hairs white, hairs straight or irregularly branched or stellate, hairs appressed or spreading. Blade margins entire (probably never slightly dentate), with non-glandular hairs (often stiffly simple cilia); apices acute.
Reproductive morphology. Flowering stems with leaves (1–4). Flowering stem hairs branched (irregularly and very dense near the inflorescence); shorter than the diameter of the flowering stem; white or translucent. Inflorescences head-like (in bud), or racemose (soon elongating); dense (in bud), or diffuse (soon elongating); globose or sub-globose (in bud), or oblong, or lanceolate; elongating as the fruit matures. Pedicels with non-glandular hairs (pedicels are densely pubescent). Flowers per inflorescence (2–)5–13(–16); small. Sepals conventional; 4; free; 0.7–1.2 mm long; (1.5–)2–2.5 mm wide; green, or purple (tinged, with hyaline margins towards the apex); herbaceous (centre), or scarious (margins). Calyx without sessile glands; hairy (with usually simple hairs in the upper half). Calyx hairs non-glandular; white or translucent. Petals conventional; free; 4; white (cream in pressed specimens); without contrasting markings; spatulate (terminal end flat or slightly concave); unlobed, or slightly lobed or undulating; 3.5–5 mm long; 1.5–2.5 mm wide (at the apex, 0.2–0.3 mm wide at the base). Stamens 6; stamen filaments markedly unequal in length; stamen filaments glabrous. Anthers yellow; ovoid; 0.35–0.45 mm long. Ovary superior; carpels 2; syncarpous. Ovaries ovate; hairy. Ovary hairs very dense; white; branched (irregularly branched and approaching stellate). Styles 1; completely fused; thick and short; 0.2–0.8 mm long; straight. Stigmas per ovary 2. Placentation parietal. Ovules per ovary (12–)16–24(–28). Fruit stalked; stalk (1.5–)3–6 mm long; dry; a silique; ovoid; green at maturity, or purple (tinged at the edges); 6–7.5 mm long; 2.5–2.7(–3) mm wide; hairy (with stellate or irregularly branched hairs); surface appearing veinless; distinctly flattened; dehiscent; shedding the outer walls to expose a thin inner wall, with the seeds attached at the margins on either side. Styles persisting in fruit 3–8 mm long. Seeds (12–)20–24(–28); 0.9–1.1 mm long; brown; surfaces rugose.
Chromosome information. 2n = 48, or 56, or 64.
2n (6x) = 48. Heilborn (1927, 1941, Greenland); Böcher (1966a, Greenland); Mulligan (1971, northwestern Canada); Zhukova et al. (1973, 1977, northeastern Asia); Berkutenko and Gurzenkov (1976, northeastern Asia); Belaeva and Siplivinsky (1976, southern Siberia and Siberia); Zhukova and Petrovsky (1980, western Chukotka; 1984, northeastern Asia); Petrovsky and Zhukova (1981, Wrangel Island); Löve and Löve (1982, central Canada); Brochmann et al. (1993, northern Norway); Murray and Kelso (1997, western Alaska); Mulligan (2003);
2n (7x) = 56. Zhukova and Petrovsky (1984, northern and northeastern Asia);
2n (8x) = 64. Mulligan (1971, northwestern Canada); Zhukova and Petrovsky (1984, northern and northeastern Asia).
Ploidy levels recorded 4x, 7x, 8x.
Ecology and habitat. Substrates: river terraces, slopes; dry; sand, clay, till; with low organic content; calcareous.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec. Range in the Canadian Arctic Archipelago widespread. Common. Arctic, alpine. Arctic islands: Baffin, Ellesmere, Axel Heiberg, Parry islands, Banks, Victoria, Prince of Wales, Somerset, Southampton (and Bylot Island).
Northern hemisphere distribution. Circumpolar, or circumboreal. KaninPechora, Polar Ural Novaya Zemlya, YamalGydan, Taimyr Severnaya Zemlya, AnabarOlenyok, Kharaulakh, YanaKolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay, Ellesmere Land Peary Land, West Greenland, East Greenland.
General notes. The map for this species is based on specimens annotated by Elven when he visited CAN and DAO in May 2003.
Elven et al. (2003) considered that the Draba cinerea aggregate is composed of D. arctica, D. cinerea, D. oblongata, D. ovibovina, and D. parvisiliquosa.
Elven (personal communication, 2005) noted that there are, as indicated, several possible types, and those in herbarium G-DC correspond excellently with our current concept of the species. He had collected the species in 2004 in the type area around the town of Schigansk. These plants are also similar to those in Alaska, Canada, Greenland, and Fennoscandia.
In the North Atlantic areas, D. cinerea is comparatively southern. It occurs in southern Greenland but not in the north. In the Nordic area it is restricted to the northern boreal parts of the mainland and is replaced by D. arctica in Svalbard.
The treatment presented here is provisional pending further study.
Illustrations. • Close-up of inflorescence in early fruiting stage. Inflorescence beginning to set fruit. Nunavut, Ellesmere Island, Johan Peninsula. J. Gillett and Shchepanek 18422A. 24 July, 1979. CAN 451231. • Close-up of fruit. Fruit shorter than typical Draba arctica. N.W.T., Victoria Island, Holman. S.A. Edlund 361. 16 July, 1982. CAN 495549. • Arctic Island Distribution.
This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.
Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.
Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa..